1. Field of the Invention
The present invention relates generally to gas turbine engine, and more specifically for a turbine rotor blade with trailing edge cooling.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
A gas turbine engine, such as an industrial gas turbine (IGT) engine, a turbine includes one or more rows or stages or rotor blades that react with a hot gas stream. The efficiency of the turbine can be increased by passing a higher temperature gas stream into the turbine. However, the turbine inlet temperature is limited to the material properties of the parts exposed to the hot gas stream. The first stage stator vanes and rotor blades are exposed to the highest temperature gas stream and therefore require the most amount of cooling. However, the second stage vanes and blades also require cooling to prevent hot spots from occurring that can result in erosion and shortened part life.
Complex internal cooling circuits have been proposed to provide cooling for these airfoils and include combinations of conduction cooling, impingement cooling and film cooling. The surface of an airfoil, such as a rotor blade, can be exposed to different temperatures. The leading edge of the blade is exposed to the highest gas stream temperature. The trailing edge region of the airfoil is not exposed to the highest temperature, but is difficult to provide adequate cooling because the airfoil is very thin in this region. A thin airfoil does not provide much internal room for cooling circuits. More effective cooling will lead to a reduced trailing edge metal temperature, which results in a reduced cooling air flow requirement that improves the turbine efficiency.